Misfiring at normal speed

I saw the post about what to do but is that the same problem with a 3.4. I am having trouble missing at normal driving speed. It will sputter and sometimes even backfire. I checked the spark plugs on the right side (the easy side) and they were just fine. They have less than 15000 miles on them. I am going to check my ignition packs today. Anyone have a clue whats wrong? email me at timberwuff_5@hotmail.com
thanks guys

I am no car genius much less mechanic but on the way to go hunting the other day, a Chevy Silverado was in front of us and was doing what you described and my dad said that he thought the guy's truck may have a bad timing chain or something similiarly related and that his truck was "missing time" I dont know if that helps any, I know just enough to get me by and what I dont know I ask my dad since he was a somewhat mechanic way back when.

If it was an older chevy then it wouldnt of been the chain prob, just the timming is off. Or it may of had a cam!! ;)

The Chevy I saw was like a 94 to 97 Silverado. This was no cam...It was backfiring every once in a while and I remembered some of what dad said after I posted.
He said that the timing chain could be missing time or something to that effect and therefore one of the pistons were off causing the backfire.....if anyone has a clue as to what I am saying please help me out cause my memory sucks.

No, thats right